MANCHESTER — Some locals keep secret how good the trout fishing can be on the Batten Kill in southern Vermont.

Now the removal of a decades-old dam on the river’s east branch is expected to boost the populations of wild brown and brook trout by giving them cooler water and more spawning habitat.

“The fish are going to start to move through the site for the first time in a long time, so that’s really exciting,” said Roy Schiff, a water resource scientist and engineer working for the state.

It’s part of a larger movement to remove now-obsolete and risky dams that would cost more to repair and maintain than to remove, freeing up the rivers and restoring the ecosystem to its natural state. In Manchester, home to the American Fly Fishing Museum, some anglers are cheering the dam’s removal.

Long gone is the sawmill that the Dufresne Dam was built in 1908 to power. The pond that the dam created was later stocked with sizable fish. But the earthen dam was too small and has been leaking for many years, creating safety concerns.

Big floods over the years, including the remnants of Hurricane Irene in 2011, overtopped the dam and damaged the embankment, Schiff said.

Officials determined that removing it would cost about $200,000, which is less than the cost of repairing and maintaining it.

So crews got to work this month, taking down the concrete spillway and earthen embankment. The eight feet of accumulated sediment was pushed onto the flood plain so it wouldn’t affect the fish.

Finally, the river was restored to its original spot in the center of the channel, noted in historic plans from the 1900s.

“The nice thing about dam removals is you’re letting Mother Nature kind of take it back over so it’s not like we’re building things that have to function a certain way. We’re actually just unbuilding things that we put in the rivers that we’re not using or are unsafe,” Schiff said.

Locals might miss having a pond stocked with fish, but now they’ll have a managed fishery with wild trout, Schiff said.

“Small impoundments like this impact fisheries,” Schiff said of the former pond. “They warm the water. ... So we know that trout like cold water, so if you have these intermittent warm spots, they reduce the trout habitat.”

Some trout died during hot, dry summers because the water temperature was too high, said Tyler Atkins, an officer with Southwestern Vermont chapter of Trout Unlimited. He said he hopes that the fish having access to the cooler, spring-fed water will decrease the mortality rate. Additionally, the trout will have access to more and potentially better spawning habitat upstream, he said.

Schiff, who is also a fisherman, knows it will pay off.

He says he’s walked miles of the streams in Dorset and spotted huge trout that didn’t have access to the main part of the river because of the dam.

“So I know there’s a gap here because of this dam, and that’s going to go away for sure,” he said.